Men. Why?

PublishedJune 2, 2015

Still needed.

Biologists have recently discovered that female sawfish can reproduce without any help from male sawfish. It’s the first time that the process – known as parthenogenesis – has been observed in vertebrates.

So, let’s revisit an old question: Why do we need men? (See also here).

The default sex, of course, is the female. Things have to happen – in the right order, at the right time – to convert a female fetus into a male. First of all, the fetus has to get a Y chromosome from the father as well as an X from the mother. (Females get two Xs, one from each parent).

As it happens, the Y chromosome is petty wimpy. Estimates vary, but there are probably no more than 80 genes on the Y chromosome. The Y’s most important tasks are to create male genitalia and the testosterone needed to masculinize the brain. Some might argue that this is value subtracted rather than value added.

So if the Y chromosome doesn’t do much other than create male genitalia and we don’t need male genitalia to create babies (via parthenogenesis), then why do we need men?

Or asScience Daily puts it: “Biologists have long puzzled about how evolutionary selection, known for its ruthless requirement for efficiency, allows the existence of males — when in so many species their only contribution to reproduction are spermatozoa.”

Here’s the idea in a nutshell: Men compete, women choose. It turns out that women are pretty good at choosing the men who will produce the healthiest offspring. Given a chance to choose over the long run, women tend to make the right choices. (See also here)

The researchers, led by Professor Matt Gage, studied beetles over 50 generations. In some samples, 90 male beetles competed for the attention of 10 females. In other samples, females outnumbered males by a wide margin.

Which samples were the healthiest and survived the longest? The ones with the most competition. After 50 generations, those samples that featured the most competition and choice were the healthiest. Samples with the least competition, on the other hand, became extinct within ten generations.

As Professor Gage notes, “To be good at out-competing rivals and attracting partners in the struggle to reproduce, an individual has to be good at most things, so sexual selection provides an important and effective filter to maintain and improve population genetic health.”

So, I suppose we men should be happy. There’s still a good reason for women to keep us around.